• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.5
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• pp.492-501
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• 2007

Coastal disasters have become one of the most important issues in every coastal country. In Korea, coastal disasters such as storm surge, sea level rise and extreme weather have placed many coastal regions in danger of being exposed or damaged during subsequent storms and gradual shoreline retreat. A storm surge is an onshore gush of water associated with a tow pressure weather system, typically in typhoon season. However, it is very difficult to predict storm surge height and inundation due to the irregularity of the course and intensity of a typhoon. To provide a new scheme of typhoon damage prediction model, the scenario which changes the central pressure, the maximum wind radius, the track and the proceeding speed by corresponding previous typhoon database, was composed. The virtual typhoon scenario database was constructed with individual scenario simulation and evaluation, in which it extracted the result from the scenario database of information of the hereafter typhoon and information due to climate change. This virtual typhoon scenario database will apply damage prediction information about a typhoon. This study performed construction and analysis of the simulation system with the storm surge/coastal inundation model at Masan coastal areas, and applied method for predicting using the scenario of the storm surge.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.15-21
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• 2020

Although IoT systems are used in a variety of heterogeneous environments as cloud environments develop, all IoT devices are not provided with reliable protocols and services. This paper proposes an IoT data management technique that can extend the IoT cloud environment to an n-layer multi-level structure so that information collected from different heterogeneous IoT devices can be efficiently sorted and processed. The proposed technique aims to classify and process IoT information by transmitting routing information and weight information through wireless data link data collected from heterogeneous IoT devices. The proposed technique not only delivers information classified from IoT devices to the corresponding routing path but also improves the efficiency of IoT data processing by assigning priority according to weight information. The IoT devices used in the proposed technique use each other's reliable protocols, and queries for other IoT devices locally through a local cloud composed of hierarchical structures have features that ensure scalability because they maintain a certain cost.y channels of IoT information in order to make the most of the multiple antenna technology.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.213-219
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• 2012

Recently, we are simultaneously exposed by various electromagnetic sources due to an increase of mobile communication services. However, EMF(Electric, Magnetic and Electromagnetic Field) study has been performed mainly about only single frequency. The objective of this paper is to develop an multiple-frequency exposure system for in vitro experiment. The exposure unit for in vitro experiments was designed by radial transmission line type to get broadband characteristics to generate signals of CDMA at 836.5 MHz and WCDMA at 1950 MHz frequency simultaneously. The modulated signals were delivered to the conical antenna through amplifier, digital attenuator and RF combiner. SAR values were obtained by the averaged values of 3 measured values at 9 points in petri dish using the fiber optic temperature probe. The measured return loss was under -15 dB. For 1 W input power, the mean value and standard deviation of SAR were $0.105{\pm}0.019$ for the CDMA frequency and $0.262{\pm}0.055$ for the WCDMA frequency.

• Journal of dental hygiene science
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• v.10 no.1
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• pp.55-61
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• 2010

The main purpose of this study was to identify the service quality of some dental clinics located in Gwangju and find an association between service quality and patient's intention to re-visit the same dental clinic. The search objects were 197 patients from five dental clinics, and data collected by self-administered questionnaire which was composed general characteristics, characteristics relating to visit of clinics, quality of service, patients satisfaction and intentions to re-visit. The used statistical analysis to find the association between quality of service and intention to re-visit was multiple regression analysis. This study looked at relations between quality of dental service, service satisfaction and intentions to visit again, and found that quality of service including six service areas had a statistically significant positive correlations with satisfaction and intentions of re-visit. When this study conducted a multiple regression analysis to identify variables that influence intentions of re-visit, it found that patients revisited the dental clinic only when quality of service was included. In conclusion, quality of service evaluated by patients influenced on their intention of re-visit and especially. Therefore, this study concludes that improvement in satisfaction and intentions of re-visit relies on Accessibility, that is, providing of medical information, consultant telephone, how delivery the dental medical system is. Service quality of dental institutes measured by SERVQUAL model and intention to re-visit.

• The Journal of the Acoustical Society of Korea
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• v.23 no.1
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• pp.8-16
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• 2004

An inversion method is presented for the determination of the compressional wave speed, compressional wave attenuation, thickness of the sediment layer and density as a function of depth for a horizontally stratified ocean bottom. An experiment for estimating those properties was conducted in the shallow water of South Sea in Korea. In the experiment, a light bulb implosion and the propagating sound were measured using a VLA (vertical line array). As a method for estimating the geoacoustic properties, a coherent broadband matched field processing combined with Genetic Algorithm was employed. When a time-dependent signal is very short, the Fourier transform results are not accurate, since the frequency components are not locatable in time and the windowed Fourier transform is limited by the length of the window. However, it is possible to do this using the wavelet transform a transform that yields a time-frequency representation of a signal. In this study, this transform is used to identify and extract the acoustic components from multipath time series. The inversion is formulated as an optimization problem which maximizes the cost function defined as a normalized correlation between the measured and modeled signals in the wavelet transform coefficient vector. The experiments and procedures for deploying the light bulbs and the coherent broadband inversion method are described, and the estimated geoacoustic profile in the vicinity of the VLA site is presented.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.105-113
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• 2013

Consumer organizations usually lead the opinions of the consumers. This study was performed to investigate the perceptions and information needs of consumer organizations on food additives for the promotion of risk communication. A survey was conducted for 4 weeks in March 2012 by using a self-administered questionnaire consisting of 32 questions. Total 111 responses were collected for analysis. 'Safety (91.0%)' was the most important factor influencing the purchase of processed food, and both 'food additives (24.3%)' and 'environmental pollution (23.4%)' were considered as main risk factors. The longer the career of the members had, the higher negative perceptions on food additives (p<0.01). About 70% of the respondents who had known KFDA's researches on evaluating safety of food additives answered that researches were not enough to make sure the safety. Although lectures and other domestic organization were the main channels for getting information, 'TV' was considered as the most suitable way for it. 'Poor risk communication (32.4%)' was pointed out as the serious problem of government's food safety policy. Based on these results, consumer organizations' low level of trust on government should be overcome by continuous supply of information what they need to facilitate risk communication on food additives.

• Korean Journal of Remote Sensing
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• v.24 no.2
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• pp.189-194
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• 2008

Middle-infrared (MIR) spectral region between 3.0 and $5.0\;{\mu}m$ in wavelength is useful for observing high temperature events such as volcanic activities and forest fire. However, atmospheric effects and sun irradiance in day time has not been well studied for this MIR spectral band. The objectives of this basic study is to evaluate atmospheric effects and eventually to estimate surface temperature from a single channel MIR image, although a typical approach utilize split-window method using more than two channels. Several parameters are involved for the correction including various atmospheric data and sun-irradiance at the area of interest. To evaluate the effect of sun irradiance, MODIS MIR images acquired in day and night times were used for comparison. Atmospheric parameters were modeled by MODTRAN, and applied to a radiative transfer model for estimating the sea surface temperature. MODIS Sea Surface Temperature algorithm based upon multi-channel observation was performed in comparison with results from the radiative transfer model from a single channel. Temperature difference of the two methods was $0.89{\pm}0.54^{\circ}C$ and $1.25{\pm}0.41^{\circ}C$ from the day-time and night-time images, respectively. It is also shown that the emissivity effect has by more largely influenced on the estimated temperature than atmospheric effects. Although the test results encourage using a single channel MR observation, it must be noted that the results were obtained from water body not from land surface. Because emissivity greatly varies on land, it is very difficult to retrieval land surface temperature from a single channel MIR data.